Box stacking apparatus



July 28, 1959 H. J. (5088 2,896,519

BOX STACKING APPARATUS Filed July 1, 1957 Ir /////////2\ 41 32 W 48 F 1' T T 21 32 24; I "51 34 I 35 5og 33 21 3'7 40 41 53 :22 as o 29 4" i' j i' l 30 2o 22 23 41 1 mm |||I|II I I l *r I I F19. 62 44 2o INVEN TOR. JIAROLD J. G035 BY PM PM ATTORNE' Unite tates 7 ill BOX STACKING APPARATUS Harold J. Goss, Nashua, N.H., assignor to International Paper Box Machine Company, Nashua, N.H., a corporation of New Hampshire Application July 1, 1957, Serial No. 669,257

6 Claims. (Cl. 93-51) This invention relates to improvements in plunger and channel type box forming apparatus.

Such apparatus is well known and one type thereof, in

which the invention is especially desirable, is shown in my area to the bottom panel of the blank, whereupon the plunger moves upwardly into a folding channel to create the box. The box corners may be connected by stays,

interlocking flaps or glue flaps and the box is inverted, with the bottom up, when it enters a vertical extension of the forming channel constituting a magazine. Resilient fingers hold the formed box in the channel when the plunger retracts downwardly and each successive box moves the stack higher in the channel or channel extenslon.

In case of misfeeding of. the blanks, it will be apparent that the plunger will travel upwardly into the forming channel without a blank and cannot lift the previous box. Since no box is on the plunger, the plunger enters the box it has made on its previous stroke and usually ruins the box. This adversely affects the continued travel upwardly of the boxes in the stack causing jamming and time delay on the part of the operative.

The principal object of this invention is to provide detent means operable only when no box is on a box forming plunger for lifting previously made boxes in a l forming channel out of the path of the plunger.

Another object of the invention is to provide a plurality of elongated spring actuated stacking fingers around the periphery of a plunger, the stacking fingers being easily back foldable, to inoperable position during ordinarybox folding but offering considerable resistance to such back folding the absence of a blank, or box, on the plunger.

In the drawing, Fig. l is a fragmentary front view of section of the plunger and forming channel of a typical folding machine showing a flat box blank on the plunger, a completed box in the channel and stacking fingers on the plunger.

Fig. 2 is similar to Fig. 1 and shows the plunger and channel forming a box while back folding the stacking fingers of the invention.

Fig. 3 is similar to Fig.1 and shows the box completely formed and pushing the previous box further up into the channel or magazine.

Fig. 4 is a view similar to Fig. 1 showing the plunger on its way upward without a blank and showing the stacking fingers of the invention extending laterally therefrom.

Fig. 5 is a view similar to Fig. 1 showing the stacking fingers of the invention pushing the previous box up out 2,896,519 Patented July 28, 1959 "ice Fig. 7 is a side view of the device shown in Fig. 6 and Fig. 8 is a perspective view of a plunger constructed in accordance with the invention.

As shown, 20 is a box forming plunger constructed in accordance with the invention, and 21 is a box forming channel cooperable with the plunger 20. Plunger 20 reciprocates axially of channel 21 by any suitable mechanism well known in the art and therefore not shown. It will be understood that, as shown in Fig. 1, flat boxblanks such as 22 are delivered individually and successively onto the face 23 of plunger 20, the face 23 being substantially equal in area to the area of the bottom panel 24 of the blanks 22. Thereupon the plunger 20 advances axially up to and into the channel 21 whereby the wall panels such as 25 and 26 of the blanks 22 are erected'on their fold or crease lines 27 and 28 by the curved mouth elements 29 and 30 of channel 21.

The mechanism for delivering blanks to the plunger 20 and the mechanism for forming various types of folding boxes in channel 21 is not illustrated since it forms no part of this invention and is well understood by those skilled in the art. However, the particular channel 21 selected for illustration is of the type which includes a channel extension 32 (best shown in Fig. 5) into which completed boxes are pushed by the action of plunger 20. The channel extension 32, as illustrated, constitutes a vertical magazine for holding a vertical stack of inverted boxes, one above the other, the bottom panels 24 being foremost and the box rims 33 facing toward plunger face 23. Suitable resilient catches such as 34 and 35 are positioned on opposite sides of channel 21, to move inwardly under the rim 33 of each successive box 36 formed by plunger 20 and strip the box from the plunger during the retraction stroke thereof. Upon the next advancing stroke of the plunger 20, the box formed thereon such as 37 engages the rim 33 of the previous box 36 and pushes the latter further into the channel, or channel extension.

As thus far described, the above mechanism is old and well known, but it has the disadvantage that when a misfeed occurs, or when feedingis stopped, and the folding continues to clear the machine, there is no blank on the plunger 20. In such case, the plunger 20 advances on its usual stroke up into channel 21and instead of pushing the previous box suchas 37 higher, the plunger either enters the previous box 37 or engages the same irregularly to thereby deform and distort it. This continues with each successive stroke of the plunger and causes jamming of the machine, disruption of the stack and requires the removal of the stack to clear out the ruined box or boxes.

To overcome this disadvantage. in the apparatus of this invention, movable detent means is provided on the plunger 20. At least two and preferably four detents, or stacking fingers, 38, 39, 40 and 41 are mounted on the periphery of the face 23 of plunger 20 as shown in Fig. 8. Each detent such as 40 is pivoted at one end 43 on a pin 44, mounted proximate the plane of the face 23 of plunger 20, and the other end 45 is normally urged outwardly by a coil spring 46 to cause the box engaging face 47 of the detent to be coplanar with the face 23 of the plunger 2G. The detents such as 46 could be only long enough to extend into the path of, and engage, the rim 33 of a box such as 36 when in normal extended position. However, the detents are intended to easily fold back into the box form grooves such as 48 of plunger 20 when a box is being folded on the plunger. If the detents are too short there would be insuflicient leverage to easily overcome the pressure of spring 46 and instead of folding out of the way, the detents would tend to fracture the wall panels 25.

The detents 40 of this invention, therefore, are elongated and preferably are about equal in length to half the corresponding dimension of the wall panels 25. As best shown in Fig. 2 the free terminal tip 49 of each detent such as 40 is engaged by the wall panel 25 at a considerable distance fromthe fold, line, 27 and the panel 25 exerts sufficient ,leverageto easilyf overcome spring 46 during normal folding of a box.

As shown in Figs. 4 andS, however, when no blank 22 is on the plunger.20the detents 38, 3%, 40 and 41 remain in their normal outwardly extended position and no part of channel 21, or of any box, engages the outer portion of the detents. .Instead, the rim, 33"of the previously formed box 37 is engaged by the detents relatively close to thepivot axisformed by pin v.44 in, an area where leverage is low and spring resistance is correspondingly high,v The detents, therefore, dofnotfold. backwardly butpushtheboxS'l. further into the channel or. channel extension-out of the way of the plunger. Regardlessof how manytimes the plunger thereafter engages-box 37, whileempty, the box 37 is merely pushedout of the way rather than damaged.

It should be noted that the detents 38,39, 40 and 41 are preferably oppositely disposed in pairs on plunger 24 and opposite longitudinal openings such as 50 and St in the walls of channel 21 so that they do not engage the channel when normally extended as in Figs. 4 and 5. Preferably also each pair of detents 38 and 40, and 39 and 41 are mounted on strips such as 52 or 53 affixed to the edge of the plunger head or plate 54- by screws 55.

Each strip 52"or 53 includes recesses 56 and S7 to accommodate the back folding of the detents and also includes ears such as 60, 61 and 62 for supporting the pins 44. When backfolded, as shown in Fig. 3, the detents 38,39, 40 and 41 are entirelywithin the area or confines ,of the plunger 20 and ,do not interfere with any of the. box folding, glueing or other customary operations in the channel 21.

I claim:

1. In plunger and channel apparatus for erecting tray boxes, said apparatus being of the type having a box magazine in extension of said channel for holding a stack of boxes folded, and advanced bottom foremost, by said apparatus, the combination of detent means having a face normallycoplanar with the face of said plunger and normally extending outwardly from said plunger into the path of the rim of a box already formed by said plunger, said detent means being pivotally mounted on said plunger proximate. theplane ofthe plunger face and, movable to.a position within the confines of said plungerby the folding of a box blank around said plunger in said channel.

2. A combination as specified in claim 1 wherein said detent means comprises a pair of spaced apart elongated, stacking fingers on each opposite side of said plunger, each finger having one end. pivoted within the normal area of said plunger and having its free terminal end urged outwardlyvto a normal position in extension of the area of the face of said plunger by a spring.

3. A combination as specified in claim 1 wherein said detent means comprises four, elongated, stacking fingers, each adapted to fold within the confines of said plunger during the formation of a box by said plunger and spring means associated with said fingersand adapted to unfold the same into edgewise extension of said plunger in the absence of a box thereon.

4. A combination as specified in claim 1 wherein said detent meanscomprises a plurality of elongated, 'r'esiliently mounted stacking elements spaced around the periphery of said plunger, each oppositea longitudinal opening in said channel whereby said elements may advance axially of said channel in normal outwardly extending position in the absence of a blank on said plunger.-

5. In plunger and channel apparatus for erecting folding boxes of the type in which each successive box folded by saidplunger advances the previous box further along imate the plane of the plunger face and withinlthe' con fines thereof, and each having a face normally'coplanar with the face of said plunger but extending outside the area thereof for a substantial lateral distance, saiddetents being adapted to be pivoted entirely within the confines of saidplunger by the walls of a box being folded'in said channel but to engage the rim of the previous box foldedfor advancing the same further into said channel inthe absence of a blank on said plunger.

6. A combination as specified in claim 5 wherein'said detents are of sufiicient length to extend from the periphcry of the face of said plunger to proximate the midpoints References Cited. in the file of this patent '1 UNITED STATES PATENTS 1,365,920.. Ioslin Jan. 18, "1921 Watson Mar...13, 1956 

